How do you solve (x + 4)^2 = 81 using the square root property?

Aug 13, 2015

The solutions are
color(blue)(x=5, x=-13

Explanation:

The square root property involves taking the square root of both the terms on either side of the equation.

Applying the same to the given equation:

sqrt((x+4)^2)=sqrt(81

(sqrt81= color(blue)(+-9)

So,
sqrt((x+4)^2)=color(blue)(+-9

(x+4)=color(blue)(+-9

Solution 1:
$x + 4 = + 9$
Isolating $x$
$x + 4 - \textcolor{b l u e}{4} = + 9 - \textcolor{b l u e}{4}$
color(blue)(x=5

Solution 2:
$x + 4 = - 9$
Isolating $x$
$x + 4 - \textcolor{b l u e}{4} = - 9 - \textcolor{b l u e}{4}$
color(blue)(x=-13